This invention relates to a breathing circuit for a patient, and more particularly to a gas sampling tube of a respirator or anesthesia system.
Respiratory therapy and anesthesia systems include an inhalation tube for conducting fresh gas to a patient and an exhalation tube for conducting gas away from the patient. The two tubes are usually joined to a Y-piece which in turn is coupled to a face mask or a trach tube. Such a system may also include a gas sampling tube which removes samples of the gas and feeds the samples to a gas analyzer. In a respiratory therapy system, the CO.sub.2 in the gas is analyzed, and in an anesthesia system a number of gases may be analyzed.
Numerous prior art patents show such systems, and the following is a list of U.S. Pat. Nos. relating to breathing systems:
______________________________________ U.S. Pat. No. Patentee Date ______________________________________ 4,914,720 KNODLE ET AL. 04-03-90 4,852,563 GROSS 08-01-89 4,850,371 BROADHURST ET AL. 07-25-89 4,846,167 TIBBALS 07-11-89 4,840,172 AUGUSTINE ET AL. 06-20-89 4,827,921 RUGHEIMER 05-09-89 4,821,736 WATSON 04-18-89 4,815,459 BERAN 03-28-89 4,774,940 LINDER 10-04-88 4,677,987 CHOKSI 07-07-87 4,637,384 SCHROEDER 01-20-87 4,621,634 NOWACKI ET AL. 11-11-86 4,558,709 AIDA ET AL. 12-17-85 4,558,708 LABUDA 12-17-85 4,456,014 BUCK ET AL. 06-26-84 4,346,584 BOEHRINGER 08-31-82 4,297,871 WRIGHT ET AL. 11-03-81 4,221,130 BURROWS 09-09-80 4,202,352 OSBORN 05-13-80 4,197,858 OSBORN 04-15-80 4,178,919 HALL 12-18-79 3,927,670 TURNEY ET AL. 12-23-75 3,910,261 RAGSDALE ET AL. 10-07-75 ______________________________________
The P.V. Choksi U.S. Pat. No. 4,677,987, for example, shows a variety of structures including a sampling tube, wherein the sampling tube extends through the wall of a gas tube of a breathing circuit. FIG. 2 of this patent shows a sampling tube pressed through a hole formed in an elbow and extending along the axis of one arm of the elbow.
In such a system it is an advantage to be able to adjust the position of the sampling tube to obtain an accurate measurement or analysis of both the inhaled and exhaled gases. It is also important that the system be inexpensive and have a minimum risk of harming the patient.
It is therefore a general object of the present invention to provide an improved arrangement of a gas sampling tube in a breathing system.